Low cost low profile inflatable bone tamp

ABSTRACT

An inflatable bone tamp for performing a minimally invasive surgical procedure includes a shaft having a primary region and a reduced diameter region, and an inflatable structure surrounding at least a portion of the reduced diameter region. The reduced diameter region of the shaft allows the deflated size of the inflatable structure to be minimized, while at the same time eliminating the need for the conventional dual lumen balloon catheter construction.

FIELD OF THE INVENTION

The invention relates to a system and method for performing a surgicalprocedure, and in particular, to an inflatable device that incorporatesa catheter with a reduced diameter distal region for improvedmanufacturability.

BACKGROUND OF THE INVENTION

A minimally invasive procedure is a medical procedure that is performedthrough the skin or an anatomical opening. In contrast to an openprocedure for the same purpose, a minimally invasive procedure willgenerally be less traumatic to the patient and result in a reducedrecovery period.

However, there are numerous challenges that minimally invasiveprocedures present. For example, minimally invasive, procedures aretypically more time consuming than their open procedure analogues due tothe challenges of working within a constrained operative pathway. Inaddition, without direct visual feedback into the operative location,accurately selecting, sizing, placing, and/or applying minimallyinvasive surgical instruments and/or treatment materials/devices can bedifficult.

For example, for many individuals in our aging world population,undiagnosed and/or untreatable bone strength losses have weakened theseindividuals' bones to a point that even normal daily activities pose asignificant threat of fracture. In one common scenario, when the bonesof the spine are sufficiently weakened, the compressive forces in thespine can cause fracture and/or deformation of the vertebral bodies. Forsufficiently weakened bone, even normal daily activities like walkingdown steps or carrying groceries can cause a collapse of one or morespinal bones. A fracture of the vertebral body in this manner istypically referred to as a vertebral compression fracture. Othercommonly occurring fractures resulting from weakened bones can includehip, wrist, knee and ankle fractures, to name a few.

Fractures such as vertebral compression fractures often result inepisodes of pain that are chronic and intense. Aside from the paincaused by the fracture itself, the involvement of the spinal column canresult in pinched and/or damaged nerves, causing paralysis, loss offunction, and intense pain which radiates throughout the patient's body.Even where nerves are not affected, however, the intense pain associatedwith all types of fractures is debilitating, resulting in a great dealof stress, impaired mobility and other long-term consequences. Forexample, progressive spinal fractures can, over time, cause seriousdeformation of the spine (“kyphosis”), giving an individual ahunched-back appearance, and can also result in significantly reducedlung capacity and increased mortality.

Because patients with, these problems are typically older, and oftensuffer from various other significant health complications, many ofthese individuals are unable to tolerate invasive surgery. Therefore, inan effort to more effectively and directly treat vertebral compressionfractures, minimally invasive techniques such as, vertebroplasty and,subsequently, kyphoplasty, have been developed. Vertebroplasty involvesthe injection of a flowable reinforcing material, usuallypolymethylmethacrylate (PMMA—commonly known as bone cement), into afractured, weakened, or diseased vertebral body. Shortly afterinjection, the liquid filling material hardens or polymerizes, desirablysupporting the vertebral body internally, alleviating pain andpreventing further collapse of the injected vertebral body.

Because the liquid bone cement naturally follows the path of leastresistance within bone, and because the small-diameter needles used todeliver bone cement in vertebroplasty procedure require either highdelivery pressures and/or less viscous bone cements, ensuring that thebone cement remains within the already compromised vertebral body is asignificant concern in vertebroplasty procedures. Kyphoplasty addressesthis issue by first creating a cavity within the vertebral body (e.g.,with an inflatable balloon) and then filling that cavity with bonefiller material. The cavity provides a natural containment region thatminimizes the risk of bone filler material escape from the vertebralbody. An additional benefit of kyphoplasty is that the creation of thecavity can also restore the original height of the vertebral body,further enhancing the benefit of the procedure.

Conventional inflatable bone tamps (IBTs) used in kyphoplasty proceduresincorporate a “dual lumen” construction, in which a balloon is connectedbetween distal tips of coaxial catheters, such that an inflation pathfor the balloon is defined between the coaxial catheters. However, inmany instances, it can be desirable to reduce the production andmanufacturing complexity associated with the assembly of thisconventional dual lumen IBT construction.

Accordingly, it is desirable to provide an IBT that can be costs and,complexity.

SUMMARY OF THE INVENTION

By providing a bone tamp with an inflatable structure having anexpansion profile that exhibits greater distal expansion than proximalexpansion (i.e., outwardly tapering), a kyphoplasty procedure can beperformed in which lifting forces are more effectively applied to theendplates of a collapsed vertebral body, thereby enhancing thelikelihood of height restoration of the vertebral body during theprocedure.

As used herein, “expansion profile” refers to the shape of an inflatablestructure during elastic expansion of the structure (i.e., expansionbeyond the inflated, non-distended state of the structure). Furthermore,“outwardly tapering” refers to a state in which a maximum dimension(e.g., radial diameter, radial width or height) of a proximal half ofthe inflatable structure is less than a maximum dimension of a distalhalf of the inflatable structure.

In one embodiment, an inflatable bone tamp can include an inflatablestructure formed from multiple curved lobes, such as a proximal lobe anda distal lobe. By sizing the distal lobe(s) to have a larger maximumnon-distended radial diameter larger than a maximum non-distended radialdiameter of the proximal lobe(s), the inflatable structure will exhibitan outwardly tapering profile when inflated.

In various other embodiments, an outwardly tapering inflation profilecan be incorporated into an inflatable structure via features on thesurface of an inflatable element (e.g., regions of additional materialsuch as strips or bands), features within an inflatable element (e.g.,internal webbing or straps), wall thickness variations in an inflatableelement, or even external restraints that fit over an inflatable element(e.g., stents, sleeves, or strings).

In another embodiment, a surgical system for treating bone can includeone or more inflatable bone tamps exhibiting outwardly taperinginflation profiles. The surgical system can further include additionalequipment for performing a surgical procedure (e.g., one or morecannulas sized to accept the inflatable bone tamps, access tools such asdrills, guide wires, obturators, trocars, and/or curettes) and/orinstructions for performing the surgical procedure using the one or moreinflatable bone tamps.

In various other embodiments, a surgical procedure such as kyphoplastycan be performed by creating an access path using a cannula, insertingan inflatable bone tamp having an outwardly tapering inflation profileinto a target bone (e.g., a fractured vertebra) via the cannula,inflating the bone tamp to create a cavity in cancellous bone andrestore the original cortical bone profile (e.g., restore vertebral bodyheight), deflating and removing the inflatable bone tamp, and thenfilling the cavity with bone filler material to support the treatedbone.

In a procedure such as kyphoplasty, the outwardly tapering expansionprofile of the inflatable bone tamp allows the inflation force of thebone tamp to be more effectively directed towards the endplates of thefractured vertebra. This in turn enhances the ability of the bone tampto restore the height of the vertebra, rather than simply compacting alarger portion of cancellous bone within the vertebra.

As will be realized by those of skilled in the art, many differentembodiments of an inflatable bone tamp exhibiting an outwardly taperingexpansion profile, systems, kits, and/or methods of using such aninflatable bone tamp according to the present invention are possible.Additional uses, advantages, and features of the invention are set forthin the illustrative embodiments discussed in the detailed descriptionherein and will become more apparent to those skilled in the art uponexamination of the following.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1B show an exemplary inflatable bone tamp that incorporates asingle catheter having a reduced-diameter distal region.

FIG. 2 shows a kit that includes the inflatable bone tamp of FIGS.1A-1B.

FIGS. 3A-3G show an exemplary kyphoplasty procedure using the inflatablebone tamp of FIGS. 1A-1B.

FIG. 4 shows a flow diagram for an exemplary surgical procedure usingthe inflatable bone tamp of FIGS. 1A-1B.

DETAILED DESCRIPTION

By incorporating a catheter having a reduced-diameter distal region intoan inflatable bone tamp (IBT), the cost associated with manufacturingthe IBT may be significantly reduced while still maintaining IBTperformance.

FIG. 1A shows an embodiment of an inflatable bone tamp 100 that includesa shaft 120 (e.g., a catheter), an inflatable structure 110 (e.g., aballoon) at the distal end of shaft 120, and a connector 140 (e.g., aLuer Lock fitting) at the proximal end of shaft 120. Note that whileconnector 140 is depicted as a “Y” connector (i.e., two fittings orports) for exemplary purposes, connector 140 can take any shape and caninclude any number of fittings. Shaft 120 includes primary region 120Phaving a diameter D1 and a reduced diameter region 120R having adiameter D2. Diameter D2 is less than diameter D1, with this change indiameter occurring at a transition region 120T.

In various embodiments, shaft 120 can be formed from any material thatcan take the desired shaft shape, such as silicone, polyvinyl chloride,latex rubber, polyethylene, polyurethane, Nitinol, or stainless steel,among others. Note also that while transition region 120T is depicted asa conically tapering region from diameter D1 to diameter D2 forexemplary purposes, in various other embodiments, transition region 120Tcan take any shape, such as a step (or multi-step) transition or acurved transition.

A distal end region of inflatable structure 110 is coupled to reduceddiameter region 120R, such that at least a portion of reduced diameterregion 120R is enclosed within inflatable structure 110. For exemplarypurposes, the proximal end region of inflatable structure 110 is showncoupled to primary region 120P of shaft 120, although in various otherembodiments, the proximal end region of inflatable structure 110 can becoupled to reduced diameter region 120R and/or transition region 120T.

Inflatable structure 110 also encloses one or more inflation ports 125that are in communication with an interior lumen 120L of shaft 120,thereby allowing inflation fluid (e.g., saline, contrast solution, orair, among others) to be delivered to the interior of inflatablestructure 110 via shaft 120. Such inflation fluid can be fed into shaft120 via one or more fitting 141 on connector 140 (as described ingreater detail below). Note that while two inflation ports 125 inreduced diameter region 120R are depicted for exemplary purposes, IBT100 can include any number of inflation ports 125 of any shape (e.g.,round or slot-shaped, among others), size(s), and/or location (e.g., inreduced diameter region 120R, transition region 120R, and/or primaryregion 120P).

Inflatable structure 110 can be formed from any type of inflatablematerial, including non-compliant materials (e.g., many Nylon andpolyethylene materials), semicompliant materials (e.g., manypolyurethane materials), compliant materials (e.g., latex rubber), orany combination thereof. Inflatable structure 110 can also have anysize/shape. While a dual-lobed (“peanut shaped”) configuration sdepicted for exemplary purposes, in various other embodiments,inflatable structure 110 can be ovoid, spheroid, cylindrical, or anyother shape.

In some embodiments, an optional stiffening stylet 130 (e.g., stainlesssteel, Nitinol, or any other supportive material) can be removably orpermanently inserted into lumen 120L of shaft 120 to provide someadditional rigidity to reduced diameter region 120R and/or inflatablestructure 110 (for example, to assist with placement, inflation, and/orremoval of inflatable bone tamp 100 during a surgical procedure). Invarious embodiments, stylet 130 can include a cap or cover 130C forsecuring and sealing to connector 140 (e.g., via a threaded or lockinginterface).

Note that typically, the distal end of, reduced diameter region 120R isclosed off to prevent unwanted material ingress into lumen 120L and toenable high pressure inflation of inflatable structure 110. However, invarious embodiments, optional stiffening stylet 130 can be used to sealthe distal end of reduced diameter region 120R (e.g., the diameter ofstylet 130 can be the same as or slightly larger than the inner diameterof reduced diameter region 120R, or stylet 130 can include one or morefeatures to engage with and seal off reduced diameter region 120R),thereby allowing lumen 120L to be used for non-inflation operations aswell (e.g., aspiration or irrigation).

In another embodiment, one or more radiopaque markers 120M can be placedat one or more locations on inflatable bone tamp 100 to assist invisualization of inflatable bone tamp 100 during a surgical procedure.Note that although a single marker 120M positioned at the proximal endregion of reduced diameter region 120R is shown for exemplary purposes,in various other embodiments, markers 120M can additionally oralternatively be placed at any number of locations on inflatable bonetamp 100. In various other embodiments, some or all of shaft 120 and/orsome or all of inflatable structure 110 can be formed from or canincorporate radiopaque materials, markings, or structures.

FIG. 1B shows inflatable bone tamp 100 with inflatable structure 110fully deflated around reduced diameter region 120R of shaft 120. Reduceddiameter region 120R beneficially allows inflatable structure 110 tohave a more compact deflated profile than would be possible ifinflatable structure 110 were mounted solely upon primary region 120Pand its larger diameter D1. This in turn allows inflatable bone tamp 100to be more readily maneuvered and delivered through a smaller cannula,thereby beneficially enhancing the suitability of inflatable bone tamp100 for use in minimally invasive surgical procedures.

FIG. 2 shows a diagram of a kit 200 for use in performing a surgicalprocedure (e.g., a kyphoplasty procedure described with respect to FIGS.3A-3G below). Kit 200 includes an inflatable bone tamp 100 (as describedabove with respect to FIGS. 1A-1B) that incorporates an inflatablestructure 110 mounted at least partially about a reduced diameter region120R of a shaft 120. In various embodiments, kit 200 can furtherinclude, optional additional instruments 201, such as a cannula 204sized to receive inflatable bone tamp 100, an introducer, guide pindrill curette, and/or access needle, among others (only cannula 204 isshown for clarity). In various other embodiments, kit 200 can furtherinclude optional directions for use 202 that provide instructions forusing inflatable bone tamp 100 and optional additional instruments 201(e.g., instructions, for performing a kyphoplasty procedure usinginflatable bone tamp 100 and optional additional instruments 201).

FIGS. 3A-3G show an exemplary kyphoplasty procedure using an inflatablebone tamp 100 as described with respect to FIGS. 1A-1B above. FIG. 3Ashows a portion of a human vertebral column having vertebrae 301, 302,and 303. Vertebra 302 has collapsed due to a vertebral compressionfracture (VCF) 302-F that could be the result of osteoporosis,cancer-related weakening of the bone, and/or physical trauma. Theabnormal curvature CK of the spine caused by VCF 302-F can lead tosevere pain and further fracturing of adjacent vertebral bodies.

FIG. 3B shows a cannula 304 being positioned next to the target surgicallocation, which in this case is the cancellous bone structure 302-Cwithin fractured vertebra 302. In this manner, a percutaneous path tovertebra 302 is provided via an interior lumen 304-L of cannula 304.Typically, cannula 304 is docked into the exterior wall of the vertebralbody (using either a transpedicular or extrapedicular approach) using aguide needle and/or dissector, after which a drill or other access tool(not shown) is used to create a path further into the cancellous bone302-C of vertebra 302. However, any other method of cannula placementcan be used to position cannula 304.

Then in FIG. 3C, an inflatable bone tamp 100 is placed into cannula 304.Inflatable bone tamp 100 includes a shaft 120 (e.g., a catheter), aninflatable structure 110 (e.g., a balloon) at the distal end of shaft120, and a connector 140 (e.g., a Luer Lock fitting) at the proximal endof shaft 120. Inflatable bone tamp 100 is coupled to inflation mechanism310 by a flow channel 320 (e.g., flexible tubing). For exemplarypurposes, inflation mechanism 310 is depicted as a syringe having aplunger 313 for expressing inflation fluid 315 (e.g., saline solution,air, contrast solution, or any other fluid) from a barrel 311. Note thatin various other embodiments, inflation mechanism 310 can be any systemfor delivering inflation, such as a syringe, pump, or compressed gassystem, among others. Furthermore, in various other embodiments,inflation mechanism 310 can be directly connected to inflatable bonetamp 140.

Shaft 120 is used to position inflatable structure 110 at a desiredlocation within cancellous bone 302-C. As noted above with respect toFIG. 1B, in some embodiments, inflatable bone tamp 100 can include oneor more radiopaque markers, markings, or materials to facilitate thisplacement under remote, visualization (e.g., fluoroscopicvisualization). In some embodiments, inflatable structure 110 can beplaced into a pre-formed channel or cavity 330 in cancellous bone 302-C(e.g., formed by a drill, obturator, or other instrument). In otherembodiments, inflatable structure 110 can be used to form its own pathwithin cancellous bone 302-C (e.g., due to inherent stiffness or inconjunction with a stiffening member, such as stylet 130 described abovewith respect to FIG. 1A).

As described above, inflatable structure 110 is mounted at leastpartially around a reduced diameter region 120R of shaft 120. Inflatablestructure 110 can therefore assume a relatively compact deflatedconfiguration about reduced diameter region 120R that can fit throughthe interior lumen 304-L of cannula 304. Reduced diameter region 120Rthereby allows inflatable structure 110 to exhibit a larger maximuminflation volume than an inflatable structure mounted on the a similarlysized shaft 120 that does not include a reduced diameter region butstill must fit through interior lumen 304-L of cannula 304.

Next, as shown in FIG. 2D, inflation mechanism 310 is actuated to driveinflation fluid 315 into inflatable structure 110, and inflatablestructure 110 expands within fractured vertebra 302. For example, in theembodiment shown in FIG. 2D, a force is applied to drive plunger 313through barrel 311, thereby expressing inflation fluid 315 through flowchannel 320, connector 140, shaft 120, and into inflatable structure110. The resulting expansion of inflatable structure 110 compresses thesurrounding cancellous bone 302-C to create a cavity within vertebra302.

In addition, as inflatable structure 110 performs this compression ofcancellous bone 302-C, it approaches the harder endplates 302-E1(inferior) and 302-E2 (superior) of vertebra 302. In many instances, thecontinued expansion of inflatable structure 110 can move endplates302-E1 and 302-E2 apart, thereby providing beneficial height restorationof fractured vertebra 302.

Once inflatable structure 110 has been expanded to a desired volumeand/or a desired height restoration has been achieved in vertebra 302,inflatable structure 110 is deflated, as shown in FIG. 3E. The reduceddiameter portion 1208 of shaft 120 allows inflatable structure 110 to becompactly deflated, thereby facilitating the withdrawal of inflatablebone tamp 100 from cannula 304 through interior lumen 304-L.

As shown in FIG. 3E, the result, of the previously described expansionprocedure is a well-defined cavity 302-V in cancellous bone 302-C, and arestoration of some or all of the original height of vertebra 302.Cavity 302-V can then be filled with bone filler material 255 (e.g.,PMMA), as shown in FIG. 3F. A delivery nozzle 353 can be insertedthrough cannula 304 and into cavity 302-V, and can then be used todirect bone filler material 355 into cavity 302-V.

As shown in FIG. 3F, in one embodiment, a quantity of bone fillermaterial 355 can be housed in a cartridge 352 attached to deliverynozzle 353. A hydraulic actuator 350 can then be used to remotelyexpress bone filler material 355 from cartridge 352 via a hydraulic line351 (e.g., cartridge 352 can include a piston that is driven by thehydraulic pressure supplied by hydraulic line 351). Note, however, thatin various other embodiments, bone filler material 355 can be deliveredto cavity 302-V in any number of different ways (e.g., a high pressurecement delivery pump that delivers the cement to nozzle 353 through aflexible line, or a syringe or other delivery device filled with bonefiller material 355 that is attached directly to nozzle 353). Inaddition, in various other embodiments, bone filler material 355 can bedelivered in multiple portions of the same or different materials (e.g.,a bone cement followed by a biologic agent).

Once the filling operation is complete, delivery nozzle 353 and cannula304 are removed from vertebra 302 (and the patients body) as shown inFIG. 3G. Upon hardening, bone, filler material 355 provides structuralsupport for vertebra 302, thereby substantially restoring the structuralintegrity of the bone and the proper musculoskeletal alignment of thespine. As shown in FIG. 3G, due to the restoration of height infractured vertebra 302, the abnormal curvature CK shown in FIG. 3A iscorrected to a normal curvature CN. In this manner, the pain andattendant side effects of a vertebral compression fracture can beaddressed by a minimally invasive kyphoplasty procedure.

Note that although a kyphoplasty procedure is depicted and described forexemplary purposes, inflatable bone tamp 100 can be similarly used inany other target surgical location in or around bone, such as a tibialplateau fracture, a proximal humerus fracture, a distal radius fracture,a calcaneus fracture, a femoral head fracture, among others. Variousother usages will be readily apparent.

FIG. 4 shows a flow diagram of a process for performing a surgicalprocedure such as kyphoplasty using an inflatable bone tampincorporating a shaft having a reduced diameter region. In a PLACECANNULA(S) step 410, a cannula is positioned within a patient to providea path to a target surgical location (e.g., as described with respect toFIG. 3B). Note that although a unilateral procedure is described abovefor clarity, in various other embodiments, a bilateral procedure can beused (e.g., placing two cannulas to provide access through both pediclesof a vertebra).

Then, in an INSERT IBT(S) WITH REDUCED DIA SHAFT(S) step 420, aninflatable bone tamp having an inflatable structure at least partiallysurrounding a reduced diameter shaft region (e.g., as described withrespect to FIGS. 1A-1B) is placed within the patient through the cannula(e.g., as described with respect to FIG. 3C). Note once again that ifmultiple cannulas have been placed in step 410, an inflatable bone tampcan be inserted into each cannula (with at least one of the inflatablebone tamps exhibiting a shaft having a reduced diameter region for theinflatable structure).

Next, in an INFLATE IBT(S) step 430, the inflatable bone tamp(s) is(are) inflated to create a cavity(ies) in cancellous bone and, ideally,at least partially restore the original cortical bone profile (e.g., asdescribed with respect to FIGS. 3D and 3E). Note that if multipleinflatable bone tamps have been introduced in step 420, their inflationcan be sequential, simultaneous, sequentially incremental (e.g.,partially inflating one before partially or fully inflating another), orany other order.

The inflatable bone tamp(s) is (are) then deflated in a DEFLATE IBT(S)step 440 (e.g., as described with respect to FIG. 3E) and withdrawn fromthe patient in a REMOVE IBT(S) step 450 (e.g., as described with respectto FIG. 3F), and in a DELIVER BONE FILLER step 460, a bone fillermaterial (e.g., bone cement) is conveyed to the cavity formed by theinflatable bone tamp to create a permanent reinforcing structure withinthe bone (e.g., as described with respect to FIGS. 3F and 3G).

Note that if multiple bone tamps have been placed within the patient(e.g., in a bilateral procedure) in step 420, one or more of thoseinflatable bone tamps can be left (inflated) within the patient toprovide support for the bone structure during subsequent materialdelivery during step 460. The process can then loop back to step 440 andthen step 450 until all inflatable bone tamps have been removed, and allthe resulting cavities in the bone have been filled with bone fillermaterial.

While various embodiments of the invention have been described above, itshould be understood that they have been presented by way of exampleonly, and not limitation. Where methods and steps described aboveindicate certain events occurring in certain order, those of ordinaryskill in the art having the benefit of this disclosure would recognizethat the ordering of certain steps may be modified and that suchmodifications are in accordance with the variations of the invention.Additionally, certain steps may be performed concurrently in a parallelprocess when possible, as well as performed sequentially as describedabove. Thus, the breadth and scope of the invention should not belimited by any of the above-described embodiments, but should be definedonly in accordance with the following claims and their equivalents.While the invention has been particularly shown and described withreference to specific embodiments thereof, it will be understood thatvarious changes in form and details may be made.

The invention claimed is:
 1. A device for performing a surgical procedure, the device comprising: an elongate shaft comprising an inner surface defining a lumen, the elongate shaft comprising a primary region having a first diameter and a secondary region having a second diameter, the first diameter being greater than the second diameter, the elongate shaft comprising a transition region that is tapered continuously between the primary region and the secondary region, the elongate shaft comprising a smooth outer surface along an entire length of the shaft; an inflatable structure including a proximal end region coupled to a distal end region of the primary region and a distal end region coupled to the secondary region such that the secondary region and the transition region each extend at least partially within an inflatable chamber of the inflatable structure; and a stylet movably positioned within the lumen and configured to provide additional rigidity to the secondary region, wherein a distal end region of the secondary region comprises a distal end surface that defines a completely closed distal end of the shaft that is configured to prevent unwanted material ingress into the lumen, the distal end surface defining a distal stop for the stylet such that a tip of the stylet engages the distal end surface.
 2. The device of claim 1, wherein the lumen is in communication with the chamber such that an inflation material may be moved through the lumen and into the inflatable chamber to increase a volume of the inflatable chamber.
 3. The device of claim 2, wherein the distal end region of the inflatable structure is coupled to the distal end region of the secondary region.
 4. The device of claim 3, wherein the secondary region comprises at least one opening defining a flow path between the lumen and the inflatable chamber.
 5. The device of claim 4, wherein: the elongate shaft extends along a longitudinal axis between the primary region and the secondary region; and the secondary region comprises at least one opening extending perpendicular to the longitudinal axis that is in communication with the lumen.
 6. The device of claim 1, wherein the elongate shaft consists of stainless steel.
 7. The device of claim 1, wherein the stylet comprises nitinol.
 8. The device of claim 1, wherein a portion of the distal end region of the inflatable structure is flush with an end surface of the closed distal end.
 9. The device of claim 1, wherein when inflated, a proximal half of the inflatable structure has a maximum interior volume that is less than that of a distal half of the inflatable structure.
 10. The device of claim 9, wherein the proximal half of the inflatable structure has a maximum radial diameter that is less than that of the distal half of the inflatable structure when the inflatable structure is inflated.
 11. The device of claim 1, wherein when inflated, the inflatable structure has an outwardly tapering expansion profile that allows an inflation force to be more effectively directed toward endplates of vertebrae.
 12. The device of claim 1, wherein when inflated, the inflatable structure has a dual-lobed, peanut shaped configuration comprising a proximal lobe and a distal lobe, the distal lobe having a larger maximum radial diameter than the proximal lobe upon inflation of the inflatable structure.
 13. A system for performing a surgical procedure, the system comprising: a cannula comprising an inner surface defining a lumen; and an inflatable bone tamp, the inflatable bone tamp comprising a shaft having a primary region and a reduced diameter region, the shaft comprising a transition region that is tapered continuously between the primary region and the reduced diameter region, the inflatable bone tamp comprising an inflatable structure including a proximal end region being coupled to a distal end region of the primary region of the shaft and a distal end region of the inflatable structure being coupled to the reduced diameter region such that at least a portion of the transition region and the reduced diameter region extend within an inflatable chamber of the inflatable structure, the shaft comprising spaced apart ports extending through inner and outer surfaces of the shaft such that the ports extend perpendicular to an axis defined by the shaft, the shaft comprising a smooth outer surface along an entire length of the shaft, the inflatable bone tamp comprising a stylet movably positioned within a lumen of the shaft, wherein the distal end region comprises a distal end surface that defines a completely closed distal end of the shaft that is configured to prevent unwanted material ingress into the lumen of the shaft, the distal end surface defining a distal stop for the stylet such that a tip of the stylet engages the distal end surface, and further wherein the inflatable structure, when deflated about the reduced diameter region, is sized to, fit through the lumen of the cannula.
 14. The system, of claim 13, wherein the stylet is configured to provide additional rigidity to the reduced diameter region.
 15. The system of claim 13, wherein the ports are each in communication with the inflatable chamber such that an inflation material may be moved from the lumen and into the inflatable chamber to increase a volume of the inflatable chamber.
 16. The system of claim 15, further comprising a connector coupled to the primary region, the stylet extending through the connector, the stylet comprising a cap having threads that engage threads on the connector to secure and seal the stylet to the connector.
 17. The system of claim 13, further comprising: a second cannula defining a second access lumen; and a second inflatable bone tamp, the second inflatable bone tamp comprising a shaft having a second primary region and a second reduced diameter region, and a second inflatable structure, wherein the second inflatable structure surrounds at least a portion of the reduced diameter region, and further wherein the second inflatable structure, when deflated about the second reduced diameter region, is sized to fit through the second access lumen.
 18. The device of claim 13, wherein a portion of the distal end region of the inflatable structure is flush with an end surface of the closed distal end.
 19. A method comprising: establishing an access path to a bone; driving an inflatable structure through the access path using an elongate shaft, wherein the shaft includes a smooth outer surface along an entire length of the shaft, a primary region and a reduced diameter region positioned at least partially within the inflatable structure, a proximal end region of the inflatable structure being coupled to a distal end region of the primary region and a distal end region of the inflatable structure being coupled to the reduced diameter region, the elongate shaft comprising a transition portion between the primary region and the reduced diameter region, the transition portion being tapered continuously between the primary region and the reduced diameter region, the distal end region comprising a completely closed distal end configured to prevent unwanted material ingress into a lumen defined by an inner surface of the elongate shaft; inserting a stylet into the lumen and moving the stylet distally until a tip of the stylet engages the closed distal end; inflating the inflatable structure to manipulate the bone; deflating the inflatable structure about the reduced diameter region; and withdrawing the inflatable structure through the access path. 